According to a recent study focusing on the period between 2013 and 2017 published in PLOS ONE, abstinence from smoking could have prevented the majority of socioeconomic inequality in the context of cancer occurrence in England. High cancer prevalence has been associated with poverty; people belonging to poor socioeconomic positions are more susceptible to cancer risk factors, such as tobacco consumption, comorbidities, and little or no access to screening and treatment. Inequities in health coverage and lifestyle factors, such as poor diet and obesity, likely play a part in the disparity. Additionally, most cancers are diagnosed at a later stage in the underprivileged population.
Cancer occurrence across the UK varies according to the socio-economic status of the affected population. Smoking accounted for approximately 44,000 cancer cases (15% of all incidences) in 2015 in England, besides being the primary reason for avoidable cancer and related-deaths in the UK. The total cancer incidence in England was 17% greater in the quintile with the lowest income, compared with their highest counterparts.
Nick Payne at Cancer Research UK and collaborators investigated if cancer cases that could be attributed to smoking could be classified according to the socio-economic status of the patient in England. They emphasized on 15 different cancer types, based on substantial evidence linking them with smoking. The contribution of smoking to more than 8 in 10 socio-economic disparity-related cancer occurrences in England laid the foundation for this research. They calculated the cancer cases attributed to smoking from 2013 to 2017 by merging smoking prevalence with cancer incidence and the comparative risk of being detected with cancer among non-smokers versus smokers. The identified cases were displayed as a percentage of the overall socioeconomic disparity-related cancer cases.
An expected 27,200 disparity-related cancer cases are identified in England each year. Nick and collaborators discovered that 21.1% of the cancer cases that were identified in the most deprived people were attributed to smoking. However, only 9.7% of the cancers identified in the least deprived people were attributed to smoking. This generated an approximately 2.2-fold difference. They mentioned that smoking prevalence similar to that of the least deprived people could have prevented more than 5,000 cancer cases or 20.3% of socio-economic disparity-related cancer cases each year.
The research team calculated the percentage of cancer cases in the deprivation quintile that could be attributed to smoking based on a formula. It suggested that more than 16,000 cancer cases or 61% of the disparity-related cancer cases could have been prevented each year if there were no smokers. Of all cancer types, lung, pharynx, esophageal, larynx, bladder, and squamous cell carcinoma were most attributable to smoking, based on data split according to the International Classification of Diseases for Oncology codes.
Findings from this study helped the authors confirm smoking as the crucial driver of cancer incidence disparities in England, thus necessitating the implementation of policy measures to reduce smoking prevalence, with explicit emphasis on the most disadvantaged and underprivileged populations. Nick and colleagues concluded that the enforcement of tobacco control policies that address smoking disparities could be cost-effective, considering their influence on lowering smoking-associated poor health, including cancer incidence. In addition, they stated that this was the first study that quantitatively evaluated the influence of smoking on socio-economic disparity-related cancer occurrence in England.
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